Comments on: What technology would I need to alert a gadget of something specific in its vicinity?

By: David F

David F — Mon, 02 Nov 2009 20:21:59 +0000

1) video capture. If the picture changes, alert the device.
2) infrared. send out a pulse of infrared light. wait for it’s reflection. Measure the time delay and divide by 2 to get distance.
3) proximity (capacitive). As the dielectric changes due to foreign objects between / near two plates, the capacitance changes.
4) ultrasonic. just like infrared, but uses sound too high to hear.
5) RF. radiate a radio signal. Watch for its reflection from metal objects.

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By: hobart_elf

hobart_elf — Mon, 02 Nov 2009 20:12:59 +0000

It depends on the properties of the item, body warmth for example.
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By: loyalist

loyalist — Mon, 02 Nov 2009 19:28:59 +0000

Now a days most cars(modern) are using a technology,which alerts with a high sonic whisling sound when ever some one passes near by.Please contact a workshop for information.
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By: zonerdck

zonerdck — Mon, 02 Nov 2009 18:47:59 +0000

ya this is a dual stage motion sensor for car alarms but it has standard 12 volt negative outputs for each zone

http://cgi.ebay.com/DEI-508D-DUAL-ZONE-MOTION-SENSOR–CLIFFORD-PYTHON-VIPER_W0QQitemZ220299758722QQcmdZViewItemQQimsxZ20081023?IMSfp=TL081023108002r8283

this is a link to a e bay ad but you can find this at any local car stereo shop the dual stage ones work better than the singal stage
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